Water provides greater resistance to movement of the appendages than does air, consequently, it has been accepted that swimming and other water sports in which a portion of the body is immersed in the water are quite useful in conditioning muscles. However, muscles develop specifically in the way in which they are trained. That is, muscular development generated by swimming or such alternatives as cycling and weight training are good secondary methods of overall conditioning for people who are not engaged in cycling, swimming or weight training as their primary sport or activity; however they do not lead to the direct development of the muscles required for other activities. Thus it should be seen that for proper training the athlete or patient, as the case may be, should utilize the correct biomechanical movements in order to properly develop his musculature. That is to say, for example, the person should engage not in swimming but rather in running immersed in and buoyed by water in order to strengthen the muscles desired for running.
Unfortunately flotation devices developed heretofore have not been designed to allow the user to perform such exercises but rather have been designed for safety purposes. The ski vests and life jackets which are used for flotation by most people are designed to keep the upper body well out of the water and to force the wearer onto his or her back to prevent drowning. Consequently such devices support the wearer in what would be an unnatural position for repetitive exercises such as running or aerobics, which will also be referred to as "running activities". Also, such devices are not designed to allow the freedom of movement associated with proper running or aerobic exercises. As a result of these shortcomings, a person attempting to use a standard ski vest or life jacket to condition himself through performing his normal exercise routine in water will find that he is utilizing muscles in a manner not normally utilized in his particular sport due to the improper positioning afforded by these flotation devices and is likely to experience at least some discomfort due to the bulkiness of such devices. Furthermore, since these devices are designed to hold the wearer substantially out of the water, the upper extremities, that is the arms and shoulders of the wearer, are generally held above the water and do not benefit greatly from the increased resistance afforded to the wearer by the water.